Early Imperial campaigns in Germania

The Early Imperial campaigns in Germania were a series of military expeditions launched by the Roman Empire into Germania, the homeland of the Germanic tribes in Central Europe. After Nero Claudius Drusus led the first expedition across the Rhine in 12 BC, campaigns across the Rhine occurred frequently until the disastrous Battle of the Teutoburg Forest in 9 AD. From 14 to 16 AD, the Roman general Germanicus led a punitive expedition which avenged the defeat, retrieving the three lost eagles of the legions destroyed at the battle, and pacifying the Germans. However, the Romans never again attempted to conquer lands to the east of the Rhine.

Background
In 27 BC, the new Roman emperor Augustus had his general Marcus Vipsanius Agrippa suppress the uprisings in Gallia, which had been supported by the Germanic tribes across the Rhine River. After Gaul was pacified, the Romans turned their attention to their troublesome Germanic neighbors in the east. From 19 to 17 BC, the Romans built several forts to protect the Rhineland. Augustus saw the future of the empire as the expansion of its borders, and Germania became the next target for expansion. In 16 BC, the Germans ambushed Marcus Lollius' Legio V Alaudae on the west bank of the Rhine, delivering a humiliating defeat after stealing the legion's eagle; Lollius later chased the Germans back into their homeland. From 16 to 13 BC, Augustus made preparations for an invasion of Germania, establishing a mint at Lugdunum (Lyon) to supply a means of coining money to pay the soldiers, organized a census for collecting taxes in Gaul, and established new military bases on the west bank of the Rhine.

Drusus' campaigns
Augustus' stepson, the experienced general Nero Claudius Drusus, was made Governor of Gaul in 13 BC, and he suppressed a Gallic uprising the following year. He built forts at Argentoratum (Strasbourg), Moguntiacum (Mainz), and Castra Vetera (Xanten), and he repelled a Germanic attack across the Rhine before launching a retaliatory attack. He then crossed the Rhine and conquered the Frisii of the Netherlands, who thereafter served as auxiliaries in his army. He then attacked the tribes of Lower Saxony before wintering back on Roman soil. The following spring, he began a second campaign, marching east to the Visurgis (Weser) River, passing through the territory of the Cherusci from the Ems to the Elbe. He marched further east into northern Europe than any other Roman general had, winning him much renown, but he had to march back to friendly territory due to depleting supplies and the coming winter. In 10 BC, he once again campaigned across the Rhine against the Chatti, conquering them and other tribes in his third campaign. In 9 BC, as consul, he began his fourth campaign, ignoring bad omens and advancing as far as the territory of the Suebi (Suebia), defeating more Germans after considerable bloodshed. He once again attacked the Cherusci, followed them across the Weser River, and pillaged everything on his way to the Elbe. On his way back to the Rhine, he fell from his horse and was badly wounded. Not long after he sent a letter to his brother Tiberius expressing his strong republican sympathies - a letter which was intercepted by his mother Livia and his stepfather Augustus - his wound became infected and he died in his tent under suspicious circumstances.

Campaigns of Tiberius
After Drusus' death, his brother Tiberius, who rode from Pavia to be by his dying brother's side, was given command of the Rhine forces. In 8 BC, he marched his army between the Rhine and the Elbe, and he came close to exterminating the Sicambri. All Germans between the Elbe and the Rhine submitted to Roman power, and Germany was essentially conquered. However, in 2 BC, conflicts with the Cherusci flared up once again, and, from 2 BC to 4 AD, Marcus Vinicius commanded the 5 legions stationed in Germany and fought against the Germans in the "vast war", defeating their resistance and earning himself a triumph in Rome. In 4 AD, Tiberius returned to command, campaigning in northern Germany for the next two years. He subdued the Cherusci and declared them to be "friends of the Roman people", and, in 5 AD, he campaigned against the Chauci and attacked into the heart of Germany both overland and by river. The Roman fleet and legions met on the Elbe, but Tiberius did not station occupying forces at the eastern position, and his army successfully defended itself against Germanic attacks as it returned to home territory. By 6 AD, the Germanic tribes had either been pacified or conquered, and the Romans planned a 12-legion attack on the last Germanic tribe, the Marcomanni, although a revolt in Illyricum forced the Romans to recognize their king Maroboduus as their rightful ruler.

Varus' campaign
After Tiberius departed to crush the Illyrian revolt, Publius Quinctilius Varus was appointed to command the remaining legions in Germania. He assumed that Germania Magna had been pacified, so he began integrating the region into the empire. He imposed civic changes upon the Germans, including a tax, which led to the Germanic tribes secretly forming a confederation led by Arminius, an Roman-educated ally of the Empire and Varus' right-hand man. In the summer of 9 AD, Varus attempted to finish the conquest of Germania with Arminius' help, but his three legions withdrew to winter on Roman soil after a tiring campaign. Arminius had Varus make a detour to quell a small tax revolt, and Arminius decided to ride ahead to garner support for the Roman cause. However, Arminius instead returned with a large Germanic army and ambushed the Romans, massacring three legions in the Battle of the Teutoburg Forest; Varus committed suicide due to the dishonor of his defeat.

Return of Tiberius
In 10 AD, Augustus sent Tiberius back to the Rhine to stabilize the frontier. He redistributed forces across the Rhineland and increased the defensive capabilities of the Rhine fortifications, and he improved discipline and led small attacks across the Rhine. He penetrated into the heart of the country, opened up military roads, devastated fields, burned houses, routed those who came against him, and returned to winter quarters without any losses. He moved slowly so as to not waste lives, and he did not focus on conquering Germania, instead launching punitive expeditions. For the campaigns of 11 and 12 AD, Tiberius was joined by his adoptive son Germanicus, and they both made excursions across the Rhine, preventing Arminius from attacking Gaul or Italy. In the winter of 12 AD, the two generals returned to Rome.

Campaigns of Germanicus
In 14 AD, Augustus died, and he left a statement in his will ordering the end of imperial expansion. Eight legions - one-third of Rome's total military forces - were stationed on the Rhine, and Germanicus was given command over them. Between 14 and 16 AD, Germanicus led Roman armies across the Rhine into Germany to avenge Varus' defeat, but the battles and skirmishes did little to change the post-Teutoburg situation. He managed to recover the three lost legion eagles, however, and he also took several captives and forced the Germanic tribes to pay tribute and make peace with Rome. Tiberius then recalled Germanicus to Rome, as he felt that the costs of Roman expansion were too great, both financially and militarily. From 9 to 16 AD, 40,000 Roman soldiers had died during the German campaigns.